In the case of MIC values, the lower the value is, the more active the extract is. If plant A above had a MIC value of 0.2 mg/ml and plant B had a MIC value of 0.1 mg/ml the total activity would be 200 mg/0.1 mg/ml i.e. 2000 ml/g for plant A and 20 mg/0.1mg/ml i.e. 200 ml/g for plant B. The units are ml/g and indicate the degree to which the active compounds in one g of plant material can be diluted and still inhibit the growth of the tested microorganism (Eloff, 2000).